Figure 2: Manual alignment of implant scan flags
Let us imagine first that our laboratory is not a place, does not have walls, and exists only in the talents of the two partners in the restorative process-the dentist and technician. The equipment they use to create the restoration may be located next to the chair or in a dental laboratory. Their "laboratory" is actually nothing more than a workflow, which is flexible to the degree that abilities, access, and equipment allow. The primary decision is the timing of the hand-off from one partner to another. Moreover, a dentist who can use optical intraoral scans for impressions and who often chooses CAD/CAM restorations as the best patient treatment option has, I believe, more freedom in the timing of the hand-off to the technician partner. The laboratory is no longer a place; it is, to a large degree, a virtual and fluid entity.
In some instances, it makes sense for the dentist to independently prepare, design, and finish the restoration chairside during a single visit using the obvious advantages of a clinical CAD/CAM system. Other times, it is advantageous to engage the services of the restorative partner (i.e., a dental technician), because he or she possesses the skill and, perhaps more importantly, the time to create restorations that either demand more complex characterization or can be more efficiently created by someone other than the dentist.
In the conventional indirect restorative process, the procedure begins with the usual steps: The clinician prepares the case according to the appropriate guidelines, makes an impression, and sends these and other critical information to the laboratory. After the laboratory receives all the materials from the dentist, the impression is poured, the models mounted, and the dies trimmed. These models are then used to fabricate appropriate restorations-either layered, pressed, milled, cast, or combinations.
Even though this application offers many advantages to the dentist-technician team, it still requires taking intraoral impressions using conventional techniques, sending these impressions to the laboratory for the creation of stone models, and fabricating traditionally created dental restorations.
In this article, we would like to explore the next phase in the evolution of the dentist-technician working relationship. Our patient was in need of a restoration to replace the missing posterior in the maxillary right quadrant. We elected not to use a conventional workflow that would have required impressions, implant impression analogs, the creation of stone models to produce a laboratory-fabricated set of implant abutments and the final restoration. Instead, we chose a completely digital method that did not require the use of traditional impression materials or the fabrication of dental models.
Once the implants were deemed ready for the restorative phase, a digital impression was created using the 3Shape Trios intraoral scanner, the maxillary-mandibular arches were scanned, and the implant positions were virtually referenced with the use of "scan flags" that were placed into each implant and scanned to create our digital file. These were then sent to the laboratory through a communication portal (figure 1).
